thws.de

Checked 22 October 2026, 00:40 UTC · via 8.8.8.8
✗Problems found
23 passed 6 warnings 1 failed 1 info

SPF

pass

SPF record published

Found

Record
v=spf1 mx a:bvbvxmail.bib-bvb.de include:spf.sendinblue.com include:_spf.o280.mx.srv.dfn.de include:_spf.kdv.bayern include:spf.protection.outlook.com ~all
DNS lookups
6 of 10
Void lookups
0 of 2

Checks

  • ✓ No deprecated ptr mechanism #1
    No ptr mechanism found in SPF record.
  • ✓ 6 of 10 DNS lookups #2
    SPF record needs 6 DNS lookups (limit is 10).
  • ✓ Ends with ~all #3
    SPF record properly uses ~all to restrict unauthorized senders.
  • ✓ Record published #6
    SPF record exists for this domain.
  • ✓ Single record #16
    Exactly one SPF record is published.
  • ✓ Valid syntax #25
    All SPF mechanisms and modifiers are valid.
  • ✓ No void lookups #26
    All include/redirect targets exist.
  • ✓ No overly broad IP ranges #27
    All ip4/ip6 ranges are narrow enough.

DMARC

fail

p=none (_dmarc.thws.de)

Found

Record
v=DMARC1; p=none; pct=100; rua=mailto:helpdesk.itsc@thws.de;
Found at
_dmarc.thws.de
TagValueMeaning
vDMARC1Version
pnonePolicy
pct100Percentage of mail the policy applies to
ruamailto:helpdesk.itsc@thws.deAggregate report addresses

Checks

  • ✗
    Policy: none (monitoring only)
    DMARC policy is set to 'none', which only monitors but doesn't protect against spoofing. Consider upgrading to 'quarantine' or ideally 'reject'.
    #4
  • ✓ Record published #5
    DMARC record exists for this domain.
  • ✓ Valid syntax #17
    DMARC record syntax is valid.
  • ✓ Aggregate reports enabled #19
    Aggregate reports are sent to: mailto:helpdesk.itsc@thws.de
  • ✓ Report addresses in own domain #29
    All report addresses are in your own organizational domain.

DKIM

warn

Selectors: mail, s1

Found

Selectors
mail, s1
_domainkey
NOERROR
SelectorKeyFlags
mailRSA 1024 bits
s1RSA 1024 bits

Checks

  • ✓ Keys found: mail, s1 #7
    DKIM keys found for this domain with selectors: mail, s1
  • !
    1024-bit DKIM key
    1024-bit RSA keys are the minimum and are considered weak today: mail (1024 bits), s1 (1024 bits). Rotate to a 2048-bit key.
    #23
  • ✓ No problematic flags #24
    No keys in test mode, revoked, or limited to SHA-1.

DNSSEC

warn

Signed, but no DS at parent

Found

DNSKEY records
Yes (4)
DS at parent
No
Algorithms
RSASHA256 (8)
Key tags
24309, 41030, 12573, 46067
Signatures valid until
27 October 2026, 00:53 UTC

Checks

  • !
    Signed, but no DS at parent
    The zone is signed (DNSKEY present) but the parent has no DS record, so the chain of trust is incomplete. Publish the DS record at your registrar.
    #8
  • !
    Signatures expire in 120h0m0s
    DNSKEY signatures expire at 2026-10-27T00:53:47Z (in 120h0m0s). Check that re-signing works.
    #21

MX

warn

3 mail servers

Found

PriorityHostRecordsReverse DNS
10a2801.mx.srv.dfn.deA 194.95.233.57a2801.mx.srv.dfn.de ✓
10b2801.mx.srv.dfn.deA 194.95.235.57b2801.mx.srv.dfn.de ✓
10c2801.mx.srv.dfn.deA 194.95.239.57c2801.mx.srv.dfn.de ✓

Checks

  • ✓ 3 MX records #9
    Found 3 MX records for this domain.
  • ✓ All hosts resolve #10
    All MX records resolve to valid IP addresses.
  • !
    Hosts without IPv6
    The following MX hosts could not be resolved to IPv6 addresses: a2801.mx.srv.dfn.de, b2801.mx.srv.dfn.de, c2801.mx.srv.dfn.de
    #11
  • ✓ Redundant MX hosts #12
    Found 3 MX records, which provides redundancy for email delivery.
  • ✓ At most 5 MX records #13
    Found 3 MX records, which is within the recommended range (1-5).
  • ✓ No localhost targets #14
    No MX records pointing to localhost found.
  • ✓ No private IP addresses #15
    No MX records resolving to private IP addresses found.
  • ✓ No CNAME targets #22
    No MX records point to a CNAME.
  • ✓ Reverse DNS confirmed #30
    All 3 MX addresss have a PTR record that resolves back to them.

TLS

warn

no MTA-STS · no TLS-RPT · DANE on 3 of 3 MX hosts

Found

DANE (TLSA records)

MX hostTLSADNSSEC
a2801.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…Yes
b2801.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…Yes
c2801.mx.srv.dfn.de3 0 1 9bec67f55f2afdb7…Yes

Checks

  • !
    Not configured
    MTA-STS is not configured, so other mail servers fall back to unencrypted delivery when TLS fails or is stripped by an attacker. Publish a _mta-sts TXT record and a policy at https://mta-sts.<domain>/.well-known/mta-sts.txt.
    #32
  • !
    Not configured
    MTA-STS or DANE is used without TLS-RPT, so you get no reports when senders fail to deliver because of TLS problems. Publish _smtp._tls TXT "v=TLSRPTv1; rua=mailto:...".
    #35
  • ✓ DANE on all MX hosts #36
    All 3 MX hosts publish DNSSEC-validated TLSA records.

BIMI

info

No BIMI record

Checks

  • i
    Not configured
    BIMI shows your logo next to your mail in supporting mail clients. It requires DMARC enforcement.
    #38